Building a demographically diverse physician-scientist workforce is crucial not only for the sake of adequate and equitable representation of underrepresented minorities in the physician-scientist workforce, but also for meeting the healthcare needs of an increasingly diverse American society and reducing health disparities. The physician-scientist workforce of biomedical researchers is comprised largely of MD graduates. MD/PhD program graduates comprise a small, but highly visible group of physician-scientists about a quarter of all MDs in biomedical research careers and only about 2% of all medical school graduates. Yet despite this small number, substantial funding supports the training of MD/PhD students. The aim is to identify the best and brightest and train them to do the type of work that will have a profound impact on our nation's and the world's health. However, not all students who enter MD/PhD programs ultimately graduate with MD/PhD degrees; and not all MD/PhD graduates pursue careers in biomedical research. In this study, we will use a mixed-methods approach. We will explore through personal interviews why some individuals entered MD/PhD programs and others did not and, of those students who entered MD/PhD programs, why some completed the MD/PhD training and others did not. We will take special care to include significant numbers of individuals from minority groups underrepresented in biomedical research. In addition, we will also seek to interview MD/PhD graduates who chose to leave a biomedical research career path and why others continue. As most physician-scientists do not have MD/PhD degrees, we also will interview students enrolled in other MD-degree programs, but who were planning substantial career involvement in research, and we will interview students who considered medical school but then pursued other graduate programs instead. This qualitative component will shed new light on why otherwise highly qualified individuals, some of whom enter medical school with interest in and expectations for substantial career involvement in research and are from racial/ethnic groups underrepresented in medicine and biomedical research, do not continue to pursue the physician-scientist career trajectory. In the quantitative component of this proposed study, we will use existing survey data from a national cohort of medical students. Our plan is to couple the findings to guide our investigations of demographic, attitudinal, and experiential factors in association with enrollment in, attrition from, and graduation from MD/PhD-degree. One of our aims is to describe demographic, pre-matriculation and medical school factors associated with sustained expectation for substantial career involvement in research at graduation among medical school matriculants. Each of the specific aims will help us identify potential targets for interventions aimed at increasing the demographic diversity of the physician-scientist workforce engaged in biomedical research.